Let’s see:
1. Much higher birthrate.
3. War-like religion promising afterlife goodies.
4. Well petro-dollar funded.
4. Well armed by Russia(Shites) and the West(Sunnis).
Back when they were stopped, only 1 out of 4 was true. Now, all 4 are happening. Good luck.
It really only takes the political will to do so. Unfortunately, western civilization seems to have a death wish.